THORACIC SURFACE ANATOMY & RELATIONSHIPS

by O.W. Henson, Jr.

University of North Carolina at Chapel Hill

Jugular (suprasternal) notch Lower border of T2

Sternal angle Disc between T4 and T5 (marks position of 2nd costal cartilage)

Xiphisternal junction Disc between T9 and Tl0

Nipple (male) 4th intercostal space near midclavicular line;

lower border of pectoralis major muscle.

Scapula

a) superior angle T2

b) spine Points to spine of T4 vertebra

c) inferior angle T7 or 7th intercostal space

Diaphragm

a) dome of right hemidiaphragm just below right nipple (male)

b) dome of left hemidiaphragm 2-3 cm below left nipple (male)

c) center of dome at or near xiphisternal junction

Lines of pleural reflection

a) from sternoclavicular joint to midline at sternal angle (both sides)

b) right line extends down midline, deviates laterally at 6th rib, crosses 8th rib at midclavicular line, 10th rib at axillary line; crosses middle of 12th rib posteriorly.

c) left line deviates laterally at 4th rib (due to heart) and then follows a line two finger breadths above the costal margin; cuts across 8th rib at midclavicular line, 10th rib at axillary line, and middle of 12th rib posteriorly.

Lungs

a) Lower borders of both lie two rib levels above the lines of pleural reflection.

b) Middle lobe (right) and lingula (left) lie immediately adjacent to heart.

c) Oblique fissure; begins medially about 5 cm lateral to the spine of T3 or T4 and runs toward the sixth costal cartilage. Follows medial border of scapula when arm is raised (hand on head).

d) Costodiaphragmatic recesses lie at, and up to, two rib levels above the lines of pleural reflection along the costal margin.

e) Horizontal fissure runs from oblique fissure at axillary line forward along the fourth costal cartilage.

Heart

a) Apex beat - near midclavicular line, 5th intercostal space.

b) Upper border - along line extending from left second costal cartilage to third right costal cartilage (l cm lateral to sternum).

c) Lower border - sternal end of right sixth costal cartilage to apex beat; must correspond to dome of diaphragm.

d) Right border - 3rd right costal cartilage to 6th right costal cartilage; convex line about l cm lateral to sternum.

e) Left border - 2nd left intercostal space (near sternum) to apex beat; convex line to left.

Heart valves Surface Projection Sound heard best

a) pulmonary 3rd left costal cartilage 2nd left intercostal space

b) aortic 3rd left intercostal space 2nd right intercostal space
c) mitral 4th left costal cartilage region of apex beat
d) tricuspid Sternum at level of 4th lower part of sternum, right intercostal space

(over the valve)

Major vessels

a) Left brachiocephalic vein Crosses behind manubrium to join right vein at level of 1st intercostal space.

b) Azygos vein Joins superior vena cava behind second costal cartilage. Arches over right main stem bronchus.

c) Aorta Arches over left main stem bronchus; middle of arch at level of sternal angle; extends down left side of vertebral column from T4 to L4.

d) Pulmonary artery Projects to area under arch of aorta.

Structures penetrating the diaphragm:

Inferior vena cava at T8

Esophagus at Tl0

Aorta at Tl2